太湖地区稻麦轮作系统氮、磷径流排放规律及流失系数

为了计算太湖地区稻麦轮作系统中氮、磷的径流排放量,通过2年的小区径流试验,研究了不同施肥方式和施肥量情况下氮、磷的流失规律及流失系数。结果表明:不同施肥处理2008年度和2009年度的全氮流失量分别为14.20~65.17 kg/hm2和38.08~77.76 kg/hm2,流失系数分别为6.02%~9.67%和3.00%~5.16%,麦季氮素的流失以硝态氮为主,而稻季则以铵态氮为主。不同施肥处理2008年度和2009年度全磷流失量分别为0.65~1.21 kg/hm2和0.72~1.15 kg/hm2,流失系数分别为-0.34%~0.19%和-0.81%~-0.15%,但不同施肥处理对径流水中总磷浓度的影响不大。施肥量、降雨时间和降雨量是影响氮、磷流失的主要因素,并且肥料深施、秸秆覆盖、节水灌溉等可在一定程度上降低氮的径流损失。     

稻麦轮作过程氨氮径流特征和数值模拟研究

通过田间定位监测和分析.研究了稻麦轮作下降雨径流过程农田NH+4-N流失的影响因素和流失特征.结果表明.稻季施肥和灌溉对降雨径流中NH+4-N流失有一定影响.麦季小麦越冬期是地表NH+4-N径流流失主要发生时期.占NH+4-N总流失量85%以上,是农田主要的污染源.根据其流失规律和特征.运用随机模型和GLEAMS模型,对稻麦NH+4-N流失进行模拟研究,其模拟值与试验值拟合度较高,NH+4-N流失估算值与实测值误差为6.17%和2.04%.     

太湖地区稻麦轮作系统不同氮肥管理模式对麦季氮素利用与流失的影响研究

通过对施氮管理模式的调整,研究太湖流域稻麦轮作系统不同模式下麦季氮素利用率以及土壤中氮素迁移对水体中氮的影响.试验设置6个处理:农户施肥处理、化肥减量处理、稻季按需施肥处理(麦季同化肥减最处理)、新型肥料处理、有机无机配施处理以及无氮处理.结果表明:有机无机配施处理在麦季持续减少25％施氮量的情况下不会影响产量及作物地上部分氮素总积累量,且氮素表观利用率显著高于其他处理,麦季径流与渗漏损失量主要受施氮量的影响,NO3-N是损失的主要形态;减氮处理可较农户处理降低7.7～12.0 kg·hm-2的氮素流失;麦季有机无机配施减量处理,能够保证作物产量与氮素吸收并且有效降低氮素的流失,具备可持续性发展的前景.     

有机-无机肥配施下氮钾的渗漏损失

连续3年5季的试验观测结果表明,稻季渗漏水中的氮以NH_4-N为主,麦季以NO_3-N和NO_2-N为主。稻季渗漏水中氮素形态的变化还因配施比例、烤田措施而变化。稻季渗漏损失的氮素主要来源于土壤氮,其中施肥的激发矿化作用对土壤氮的损失有较大影响。肥料氮直接渗漏的比例占26％～34％。稻季氮素渗漏损失量,在前期(拔节前)占全生育期总渗漏量的86％～90％,全期渗漏损失量占施氮量的18.2％～5.6％。随有机肥氮比例的增加而减少。稻季钾素渗漏量平均占施钾量的13％。肥料钾的直接渗漏损失占总渗漏钾量的75％左右。     

太湖地区稻麦轮作农田有机和常规种植模式下氮磷径流流失特征研究

为探究不同种植模式对氮磷流失的影响,采用田间径流池法,在太湖地区稻麦轮作系统中,通过连续两年田间试验,研究比较了等氮投入条件下常规种植和有机种植模式农田径流水中氮、磷浓度特征,以及径流氮、磷流失量、流失系数。结果表明,稻季和麦季农田径流中总氮、可溶性氮、铵态氮和硝态氮平均浓度和总氮流失量均表现为:常规种植有机种植对照。与常规种植相比,有机种植模式能够有效减少稻麦轮作农田中氮的径流流失,且对麦季氮素径流流失的减少效果优于稻季;尽管有机种植模式下磷流失系数低于常规种植,但有机肥投入携带的高磷量会增加农田磷素径流流失量。     

生物炭对灌淤土氮素流失及水稻产量的影响

针对宁夏引黄灌区氮素流失严重的现状,通过大田试验研究生物炭施于灌淤土对水稻产量、水稻生育期内氮素运移特征及氮素流失量的影响。在常规施肥条件下设置高量炭(C3N300:9000 kg·hm-2);中量炭(C2N300:6750 kg·hm-2);低量炭(C1N300:4500 kg·hm-2)和不施炭(C0N300:0 kg·hm-2)4个处理。研究结果表明,生物炭和氮肥配合施用,对稻田田面水和渗漏水中氮素动态有一定影响,表现为总氮(TN)和硝态氮(NO-3-N)浓度随生物炭用量增加而降低,铵态氮(NH+4-N)浓度升高;在对各层土壤氮素动态的影响上,表现为20 cm处渗漏水中氮素浓度受生物炭用量影响明显,但100 cm处氮素浓度受影响较小。对水稻生育期内氮素径流损失的影响表现为随生物炭施用量增加,田面水TN和NO-3-N径流流失风险下降,但NH+4-N径流流失风险增加;本研究条件下添加生物炭对NO-3-N和NH+4-N淋失没有表现出影响,TN淋失表现为随生物炭用量增加而降低,其中TN淋失量最小的是C3N300处理,整个生育期内淋失量为26.28 kg·hm-2,与常规施肥处理C0N300相比,减少9.45%。另外,添加生物炭增加水稻穗粒数和穗数,使水稻理论产量显著增加15.3%~44.9%,其中C3N300产量显著高于其他处理(P0.05)。生物炭用于灌淤土对水稻产量有促进作用,对降低稻田氮素淋失也表现出积极效果。     

不同施肥模式对麦稻两熟农田磷素径流流失和麦稻产量的影响

采用田间小区定位试验研究自然降雨条件下农户习惯性施肥(CK)、减量施肥(T1)及优化施肥(T2)等不同施肥模式对太湖流域麦稻两熟农田土壤磷素径流流失特征和麦稻产量的影响。结果表明:麦稻轮作农田地表径流排水主要分布于强降雨集中的水稻生长季,与降水量呈显著线性正相关关系。磷素径流流失集中在稻季,各处理的流失量占周年流失总量的66.65%—75.05%。在农户习惯性施肥(CK)条件下,麦季径流总磷平均质量浓度(0.36 mg∕L)显著高于稻季(0.19 mg∕L),但磷素径流流失量(0.47 kg∕hm~2)却显著低于稻季(1.40 kg∕hm~2)。减量施肥(T1)和优化施肥(T2)模式处理可显著降低麦季、稻季径流磷素质量浓度和麦稻周年磷素径流流失量。与CK相比,T1和T2处理显著降低麦稻周年TP径流流失量,降幅达22.62%和44.54%。在CK条件下,麦稻两熟农田磷素周年径流偏流失率达119.06 mg∕kg,T1和T2处理显著降低,偏流失率降幅达17.95%和41.22%。与CK相比,麦稻产量在T1、T2处理下均显著下降,T1与T2处理间产量无显著差异。可见,麦稻轮作种植模式下,稻季不施磷具有养分减排与作物稳产的协同效应。     

不同施肥条件下雷竹林水溶性有机碳氮的流失特征

通过建立径流场和土壤渗漏水收集装置,研究了不同施肥(常规施肥、减量施肥、微生物肥和不施肥)条件下雷竹林径流和渗漏水中水溶性有机碳(WSOC)和水溶性有机氮(WSON)的流失规律。结果表明:雷竹林地表径流(土壤渗滤)水量与降雨量之间呈极显著正相关(P0.01),WSOC、WSON的流失以渗滤迁移为主,分别占流失总量的97%和94%左右。不同施肥雷竹林WSOC流失量的大小顺序表现为常规施肥(66.66 kg·hm-2)微生物肥(63.66 kg·hm-2)减量施肥(61.06 kg·hm-2)不施肥(56.58 kg·hm-2),WSON的流失量则表现为常规施肥(37.48 kg·hm-2)减量施肥(24.40 kg·hm-2)微生物肥(21.41 kg·hm-2)不施肥(17.38 kg·hm-2)。与常规施肥相比,微生物肥和氮肥减量40%的雷竹林地WSOC、WSON流失量分别减少4.5%、8.4%和42.9%、34.9%;不同施肥雷竹林地表径流、土壤渗滤中WSON流失量分别占总氮流失量的49.2%~52.7%和26.6%~35.9%。     

稻麦轮作农田氮素流失及控制对策研究

通过2年的田间定位监测和采样分析,研究上海稻麦轮作农田氮素流失特征及对水环境的影响。结果表明,施肥对稻季地表排水、麦季径流和渗漏水中氮素流失影响显著。在粮食生产过程中过量施肥和不合理的水肥管理是土壤氮素流失的主要原因。适当减少氮肥用量,可减少农田氮素流失,且对产量影响不大。因此,改进传统的施肥模式,加快制定农业非点源污染的相关法律法规,对控制农田氮化肥流失污染和提高农业经济效益,具有十分重要的意义。     

长沙市平原旱地土壤氮磷径流特征研究

选择了长沙市具有代表性的平原旱地蔬菜基地,研究了平原旱地施肥与氮磷径流流失的关系.结果表明:在平原旱地土壤上种植蔬菜时,地表径流水中氮、磷养分的浓度主要受降雨强度和降雨量的影响,施肥量和肥料种类也是影响径流水中氮、磷养分的浓度的重要因素.从肥料流失率来看,常规施肥处理氮肥流失率最大,为1.43%,增磷处理氮肥流失率最小.为0.09%;有机肥处理磷肥流失率最大,为4.32%.常规施肥处理磷肥流失率最小,为0.48%.径流水中氮素以硝态氯形式流失为主,磷素以可溶性磷形态流失为主.     

Web2.0,以个人为中心的互联网时代的到来

本文介绍了Web2．0的知识和背景，对Web2．0出现的基础以及典型技术和应用作了阐述，同时对其作出了前景展望。     

盐胁迫对葡萄苗期多胺和激素代谢的影响

【目的】 研究盐胁迫条件下,葡萄叶片中多胺含量、多胺氧化酶、多胺合成酶活性以及激素的动态变化,研究不同盐胁迫强度对多胺类物质及激素代谢的影响。【方法】 采用盆栽基质培养模拟盐胁迫环境,设置4个NaCl处理梯度:0 (CK)、1、2和3 g/kg。多胺和激素含量的测定采用高效液相色谱法,多胺合成及分解酶活性的测定采用紫外分光光度计比色法。【结果】 盐胁迫处理后,葡萄叶片中多胺含量和脱落酸含量较对照而言显著增加,玉米素含量显著降低,随胁迫时间的延长,Put、Spm、Spd、ABA以及PAO、DAO、ADC、ODC、SAMDC活性均呈先上升后下降趋势,在10 d及10 d后达到峰值。ZT呈逐渐下降的趋势,并随胁迫强度增大而减小;进行显著性分析后,叶片中多胺含量与Put、Spm、Spd含量呈极显著正相关,DAO、ADC、ODC活性与Put含量呈显著正相关,PAO与SAMDC活性与Spm和Spd含量也呈极显著正相关。【结论】 3种多胺经酶的合成代谢后和激素共同缓解葡萄苗所遭受到的盐胁迫,期间主要发生作用的是多胺合成酶,盐胁迫下多胺与激素含量之间的变化关系也十分密切。     

市级综合气象信息分析与管理系统的设计与实现

以抚顺地区3个国家基本站50余年气象资料为依托,采用Microsoft Excel工作表实现由气候和农业气候2部分构成的气象与农业综合信息处理系统的基本思路、方法、内容、用途和使用情况。为了实现气候分析及应用的科学化、客观化、系统化、规范化、程序化及连续化的业务目标,按业务流程设计与实现的,包括资料处理、气候趋势模拟、气候预测、气候鉴定、季节性信息化处理、农作物产量预报、气候生产潜力分析等一系列内容在内的系统建设。关键是解决了大量的计算问题,建立了区域性通用模式。     

Multi-variable grey model (MGM (1,n,q)) based on genetic algorithm and its application in urban water consumption

Urban water consumption has some characteristics of grey because it is influenced by economy, population, standard of living and so on. The multi-variable grey model （MGM（1,n））, as the expansion and complement of GM（1,1） model, reveals the relationship between restriction and stimulation among variables, and the genetic algorithm has the whole optimal and parallel characteristics. In this paper, the parameter q of MGM（1,n） model was optimized, and a multi-variable grey model （MGM（1 ,n,q）） was built by using the genetic algorithm. The model was validated by examining the urban water consumption from 1990 to 2003 in Dalian City. The result indicated that the multi-variable grey model （MGM（1,n,q）） based on genetic algorithm was better than MGM（1,n） model, and the MGM（1,n） model was better than MGM（1,1） model.     

Molecular detection of virulence genes in Campylobacter species isolated from livestock production systems in South Africa

Campylobacter species are a major cause of foodborne bacterial infections in both developed and developing countries worldwide. Campylobacter jejuni is responsible for the majority of infections. This study was conducted to identify virulenceassociated genes in Campylobacter species isolated from livestock production systems in South Africa. A total of 250 fecal samples consisting of cattle(n=50), chickens(n=50), goats(n=50), sheep(n=50) and pigs(n=50) were randomly collected from livestock in Eastern Cape and KwaZulu-Natal provinces of South Africa between April and October 2018. The samples were analyzed for the presence of virulence genes in Campylobacter species using molecular PCR-based methods. It was found that 77 and 23% of Campylobacter jejuni and Campylobacter coli respectively were isolated from all the livestock samples. There were positive significant(P0.05) correlations amongst all the virulence genes that were investigated. Chisquare and Fisher's exact tests were implemented to test for the effect of livestock species on the presence or absence of virulence genes. The study demonstrated that most of livestock species can potentially cause zoonotic infections and food poisoning due to the high prevalence of Campylobacter. The high prevalence of virulence genes highlights the significance of Campylobacter in livestock production systems in South Africa. This requires the implementation of one-health approaches to reduce the impact of foodborne and zoonotic diseases for the welfare of human and animal health.     

红苕饲粮中添加铜和/或喹乙醇对猪生产性能及某些血液生化指标的影响

选体重约38公斤的长白(♂)×成华(♀)杂交猪20头,随机分为四组,饲予四种不同的饲粮,研究饲粮中添加铜和/或喹乙醇对猪生产性能和某些血液生化指标的影响。结果表明:基础组、加铜组、加喹乙醇组和两者同时加组全期日增重分别为674、761、796、678克,日采食量分别为2.50、2.65、2.74、2.40公斤,饲料利用率分别为3.73、3.49,3.44、3.54,添加铜和/或喹乙醇对试验第65天血清铜兰蛋白、尿素氨及屠宰率、背膘厚和眼肌面积无显著影响(p>0.05);添加铜使65天血清碱性碱酸酶活性极显著增高(p<0.01),添加喹乙醇有使之升高的趋势,两者同时添加时,碱性酸磷酶活性降低。     

不同施肥水平对木薯氮磷钾养分积累、分配及其产量的影响

 【目的】通过比较不同施肥水平下木薯氮磷钾养分积累、分配和产量的差异,探讨粤北坡岗地优质高产木薯氮磷钾养分的最佳用量。【方法】以木薯品种南美119为材料,采用“3414”方案,在粤北翁源进行大田试验。试验共设14个处理。【结果】施肥处理的氮素主要分配到地上部,不施肥处理的氮素则主要分配到根部;不同施肥处理的磷素均主要分配到地上部;不施肥处理和不施钾处理的钾素主要分配到根部,不施氮处理的钾素在根、冠间分配较均衡。在木薯不同生长阶段,植株氮磷钾含量均呈下降趋势,但施氮、磷、钾化学肥料处理植株氮磷钾含量的下降速度小于不施氮、磷、钾化学肥料的处理。处理N2P2K2的氮、磷、钾含量和积累量在各生育期均为最大,不施肥处理（N0P0K0）的氮、磷、钾含量和积累量在各生育期均为最小（P＜0.05）。产量最高的是N2P3K2处理,为22 694.06 kg·hm-2,其次是N2P2K2处理,为21 417.87 kg·hm-2。【结论】木薯产量、氮磷钾养分积累及其在根冠间的分配,对施肥水平高度敏感, 适当比例的氮磷钾肥配合施用既可以显著增加木薯植株的氮磷钾含量和积累量,又可以提高产量。在粤北坡岗地木薯生产中,氮素最重要,在氮素得到满足的条件下,磷素较钾素更重要。在本试验条件下,氮磷钾养分最佳用量为358.80 kgN·hm-2、89.10 kg P2O5·hm-2和187.50 kg K2O·hm-2。     

Current progress on genetic interactions of rice with rice blast and sheath blight fungi

Analysis of genetic interactions between rice and its pathogenic fungi Magnaporthe oryzae and Rhizoctonia solani should lead to a better understanding of molecular mechanisms of host resistance, and the improvement of strategies to manage rice blast and sheath blight diseases. Currently, dozens of rice resistance (R) genes against specific races of the blast fungus have been described. Among them, ten were molecularly characterized and some were widely used for breeding for genetic resistance. The Pi-ta gene was one of the best characterized rice R genes. Following the elucidation of its molecular structure, interaction, distribution, and evolution, user friendly DNA markers were developed from portions of the cloned genes to facilitate the incorporations of the Pi-ta mediated resistance into improved rice varieties using marker assisted selection (MAS). However, rice blast is still a major threat for stable rice production because of race change mutations occurring in rice fields, which often overcome added resistance based on single R genes, and these virulent races of M. oryzae pose a continued challenge for blast control. For sheath blight, progress has been made on the exploration of novel sources of resistance from wild rice relatives and indica rice cultivars. A major quantitative trait locus (QTL), named qSB9-2, was recently verified in several mapping populations with different phenotyping methods, including greenhouse methods. The ability to identify qSB9-2 using greenhouse methods should accelerate the efforts on the qSB9-2 fine mapping and positional cloning.     

Virus Location and Lymphocyte Apoptosis in Lymph Nodes of Piglets Infected with PCV-2

The present study has been performed to understand the location of the virus, type of apoptotic cells, and their relation to lymph nodes of piglets infected with porcine circovirus type Ⅱ （PCV-2）. Nine 32-day-old conventional piglets free of infection with PCV-2 were used, and distributed into three groups： control group （n = 3）, piglets inoculated with PCV-2 alone （PCV-2, n = 3）, and PCV-2 inoculated and KLH immunostimulated group （PCV-2 ＋ KLH, n = 3）. Superficial inguinal lymph nodes from all piglets were collected for histological examination after 32 days postinoculation, and immunohistochemistry for PCV-2 detection. Location of apoptotic cells was detected with TdT-mediated dUTP nick end labeling （TUNEL） and cell cycle, and the apoptotic rates were measured by flow cytometry. The characteristic histopathological lesions of the piglets in PCV-2 and PCV-2 ＋ KLH were lymphocyte depletions in the cortex and paracortex of the lymph nodes, epithelioid-like macrophage infiltration, and intracytoplasmic inclusion bodies presented in epithelioid-like macrophages. PCV-2 was mainly found in epithelioid-like macrophages by immunohistochemistry. In the lymph nodes, lymphocytes presented higher apoptotic rates in the cortex by TUNEL, special B-cell areas, and similar apoptotic cells were found in this compartment in the control. The apoptotic rates of the lymph nodes were 0.41, 3.34, and 4.88% in the control, PCV-2, and PCV-2 ＋ KLH groups by flow cytometry, respectively. The apoptotic rates of lymph nodes for PCV-2 and PCV-2 ＋ KLH piglets were significantly higher than those for the control group （P〈0.05 and P〈0.01）. The proliferation index （PI） was 0.17_＋0.01, 0.12_＋0.01 and 0.12_＋0.04 in the control, PCV-2, and PCV-2 ＋ KLH group, the PI of the control group was higher than that of the other groups, but without the statistical difference. PCV-2 can induce lymphocyte depletion in lymph nodes of piglets by blocking cell proliferation and promoting apoptosis. This is one o     

内脐蠕孢属、平脐蠕孢属和凸脐蠕孢属的研究

本文报道了平脐蠕孢属(Bipolaris)一个新种,一个新组合,5个新记录以及凸脐蠕孢属(Exserohilum)一个新记录。讨论了内脐蠕孢属(Drechslera)、平脐蠕孢属、凸脐蠕孢属与长蠕孢属(Helminthosporium)的关系,并就我国已报道的长蠕孢属真菌按Alcorn等~([1,3,4,5,24])人的意见,逐个进行了订正。